sew your own diapers

I am having trouble with closing the front panel on my 100% cotton knit outer diapers (using the VB AIO pattern). I seem to be getting a slight bit of bunching/fold(like there is too much fabric).
Any tips or ideas as to what I am doing to cause this??

I have the same problem with my PUL too??? I'm wondering if I'm not trimming exactly right or maybe I should try a longer stitch length.....IDK.....I'm at a loss......lol.

could you post a picture??  i would love to see what you mean before offering what to do next . . .provided i could actually help 

It sounds like you need to use a walking foot. It's a must for dealing with those stretchy fabrics. If you're already using it, then I too am at a loss.